Male reproductive problems may add to falling fertility rates

Paris, 29 November 2010 Reduced male fertility may be making it
even harder for couples to conceive and be contributing to low
birth rates in many countries, reveals a new European Science
Foundation (ESF) report launching today.

More than 10% of couples worldwide are infertile, contributing
to the growing demand for assisted reproduction techniques such as
in vitro fertilisation (IVF) for which Robert G. Edwards won the
Nobel Prize in Medicine last month.

Sperm counts have dropped significantly in the last 50 years in
developed countries. Today, at least one in five 18-25 year old men
in Europe have semen quality in subfertile range. Testosterone
levels are also declining. This is mirrored by increasing
testicular cancer in most industrialised countries and more
developmental abnormalities such as undescended testes. All of
these factors are linked to reduced fertility and may have common
origins during foetal development.

"The important impact of men's reproductive health on a couple's
fertility is often overlooked," said Professor Niels Skakkebæk from
the University of Copenhagen, who co-authored the report. "Women
postponing motherhood have reduced fertility, and we now see that
poor sperm may be making it even harder to conceive. While poor
sperm may be part of the reason more couples are using IVF it may
also be making those therapies less successful."

Skakkebæk continues: "We need a common strategy in Europe to
target research so we can address the poor state of men's
reproductive health. That this decrease in male reproductive health
has occurred in just a few decades suggests it's caused by
environmental and lifestyle factors rather than genetics. So it is
preventable if we correctly identify the causes."

In men some lifestyle factors such as obesity and smoking can
affect sperm counts, but the effects are small. In contrast, if
women smoke heavily in pregnancy, a much larger fall in sperm count
is likely in their sons when they grow up. Testosterone levels
naturally drop as men age, which may predispose men to
cardiovascular and metabolic health problems that pose large
financial and healthcare issues for national governments. Low sperm
counts and low testosterone levels are both associated with
increased risk of early death for men.